Hi readers! I just got back to NYC from Missoula, Montana! I was at the North American Conference for Conservation Biology. It was a good conference and I was able to present some of my work on tiger beetles and watch many of my fellow museum colleagues give great talks. I also went to a great session on invasive species- but not in the way you’d think. I’d like to take this post to summarize some of what was discussed in that session.
How do you react to the word “invasive”? It has an immediate negative connotation, so when you call a species “invasive” it sounds like a property of the species and you may automatically think about how we need to get rid of it! Well, species are only “non-native” and “invasive” because we, humans, moved them from one place to another- either on purpose or by accident. Native species, the “good” guys, are those which have evolved in a place and adapted to it. Think about your neighborhood park or backyard- or any natural area you spent time in- growing up. Does it look differently now? Were the species there when you were a kid “native”? What about those now present? There is often an emotional connection with “native” species that also makes us having negative feelings against the “invasives”. Many scholars have likened this feeling to xenophobia– or fear of foreign people- but I’m not going to get into that philosophical debate here.
One speaker at the session, Emma Marris, challenged us to conduct a “Veil of Ignorance” experiment. In other words, if we didn’t know if the species were native or not, how would we manage the site? For example, if we were managing an area- say a park- for a rare fish-eating bird as well as trying to maintain good recreation conditions, would we try to eradicate all of the grasses that cover the meadows? Why would you do this? If those grasses happen to be from another country originally, you might call them invasive and might decide to attempt to get rid of them. But would you be successful? Probably not. In the meantime, you might just use up all of your limited time and money that you could have spent attempting to improve habitat for the rare bird- such as improve water quality. The ‘Veil of Ignorance’ is a useful thought experiment when checking management priorities versus values.
Of course, there are many examples of how eradicating invasive species should be at the top of a manager’s priority list. For example, Doug Tallamy from the University of Delaware discussed how non-native trees in suburban neighborhoods support half the number of butterfly and moth caterpillars, thus drastically reducing the amount of food available to birds, and in turn, bird populations. Tallamy argued that the butterflies and moths are specifically adapted to the native trees and couldn’t effectively use the non-native trees to breed. Thus, Tallamy writes about how planting and replacing non-native with native trees and plants can greatly improve biodiversity, particularly in human dominated areas. He concluded that it is better question to ask if introduced plants have net value when managing rather than just aim to eradicate them immediately.
A final couple points raised in the discuss I found very provocative and worth thinking about were well, what about the Endangered Species Act? If, say, the Tea Party politicians caught on that conservation scientists are not as concerned about non-native species, will they use this reduced concern for native species as a reason to go after the Act? Finally, I leave you with a thought posed by Chris Thomas from York, “If we define base lines [for conservation management] as a past state, then everything is going to move away from those baselines, and we are dooming ourselves to failure.”